thanks for the reply's!!!
The maximum rated RPM is 6500 but obviosuly i dont want to run it near that!!
Thanks for the detailed info there.... i guess i dont just want straight line speed as its a bit pointless! So i would want to keep the diameter or maybe go a slight bit larger because i think there is plenty of clearance at the moment, but will going up slightly in diameter improve or reduce the performance???
Thanks for your help, if i could find a decently priced right diameter and pitched one i would buy that but i cant find one